You mention the problem of having to recompile for ABI-breaking improvements. Just out of curiosity - in the environment you're describing, how much of the code cannot be rebuilt? As I was reading I was assuming that most situations where exception handling causes performance issues are probably also situations where you have most if not all the source code available. This wasn't the case in my formative C++ years when 3rd party libs were expensive and distributed as binaries (on floppies).
